The plastics production industry is undergoing rapid evolution, driven by the need for greater sustainability and efficiency. China’s decision in 2018 to halt plastic waste imports from the West was a sudden catalyst for change. This prompted substantial investment in research and development combined with innovative design, with a strong focus on creating a more sustainable, circular lifecycle for plastics.
The current state of circularity in plastics production is characterised by a complex landscape of challenges and innovations. Although mechanical recycling remains a prevalent practice, the industry is also actively working towards enhancing recycling rates and the quality of recycled materials.
Some manufacturers are now adopting scrap-reduction machinery to minimise waste in production, and recycled bioplastics sourced from renewable materials are gaining momentum. Chemical recycling is also on the horizon, offering the potential to return recycled plastics to their original molecular state.
At the heart of this mission lie variable speed drives (VSDs) – also known as variable frequency drives (VFDs) or simply, drives – along with motors and programmable logic controllers (PLCs). Whether applied to extrusion lines, flat dye cast machinery, blown film lines, blow moulding machines or injection moulding machines, these technologies are pivotal to advancing sustainability in plastics manufacturing. Before we explore these solutions in detail, let’s lift the lid on plastic recycling’s environmental conundrum.
A paradox for plastics
While glass has been recycled for centuries, plastic was only invented 100 years ago. Because it was long regarded as a disposable material, managing its lifecycle is in comparative infancy. Given the durability of plastics, it’s no wonder then that world has found itself with a huge plastic waste crisis. According to the UN Environment Program, every year more than 280 million tons of short-lived plastic products become waste, with around 20 million tons of that spilling into oceans with devastating consequences.
It is enormously encouraging that concrete steps are being taken to combat this crisis and, within these efforts, the relatively recent emergence of plastics recycling plants is rightly hailed as a significant step towards reducing plastic waste. Indeed, while original plastic production is a major source of carbon dioxide emissions, recycling plastic saves at least 30 percent of the carbon emissions that original processing and manufacturing produces - according to Imperial College London. This is because recycling avoids the greenhouse gas emissions that would otherwise result from extracting or mining virgin materials.
But we are also in the grip of a climate crisis, and the industrial processes involved in both recycling plastics and producing recycled and bioplastics can, paradoxically, be harmful to the environment, with the most pressing concern being excessive energy consumption. To promote a truly circular lifecycle, the plastics industry must invest in energy-efficient technologies and recycling processes to reduce the environmental impact of their operations.
How drives, motors and PLCs are setting new standards for circularity
Fortunately, drives, motors and PLCs can work together to enhance energy-efficiency, reliability and overall performance of plastics production, resulting in a more circular lifecycle, and reduced total cost of ownership.
As we know, industrial motors convert electrical energy into mechanical motion to power equipment and machinery. Today’s premium motors, such as those that use synchronous reluctance (SynRM) technology, offer unparalleled levels of performance, energy efficiency, and reliability for the various applications used in plastic production both as quadric and constant torque.
Pairing motors with variable speed drives brings next-level results. Direct online motors can only be on or off, and will run at a fixed speed, regardless of the process requirements. Conversely, when motors are combined with drives like ACS580 general purpose drives, they have the ability to control and regulate the speed, torque, and position of the motor shaft accurately. Eventually, this allows for synchronisation with the motion of other equipment and motor shafts. By enabling such precision control, VSDs can significantly cut energy usage and its associated carbon emissions, as well as reduce costs.
Adding PLCs, such as the AC500 - a digital computer that executes actions via user-designed logic programs - can automate a broad variety of industrial processes and machinery for further productivity gains and cost savings. Furthermore, the sensors incorporated in the motor-drive system can gather and evaluate data to pinpoint production process inefficiencies. This enables continuous enhancement and decreased resource usage, supporting circular economy objectives with the optimal machine productivity ratio.
Whether applied to flat dye cast machinery, blown film lines, or injection moulding, these game-changing technologies are pivotal to advancing sustainability in plastics manufacturing. And an especially notable example of how these technologies combine to contribute to sustainability is in the extrusion process.